title: Efficacy of polaprezinc for acute radiation proctitis in a rat model.
abstract: OBJECTIVE
  The purpose of the present study was to standardize the experimental rat model of radiation proctitis and to examine the efficacy of polaprezinc on radiation proctitis.
  
  
  METHODS
  A total of 54 female Wistar rats (5 weeks old) were used. The rats were divided into three groups: those treated with polaprezinc (PZ+), those treated with base alone, exclusive of polaprezinc (PZ-), and those treated without any medication (control). All the rats were irradiated to the rectum. Polaprezinc was prepared as an ointment. The ointment was administered rectally each day after irradiation. All rats were killed on the 10th day after irradiation. The mucosal changes were evaluated endoscopically and pathologically. The results were graded from 0 to 4 and compared according to milder or more severe status, as applicable.
  
  
  RESULTS
  According to the endoscopic findings, the proportion of mild changes in the PZ+, PZ-, and control group was 71.4%, 25.0%, and 14.3% respectively. On pathologic examination, the proportion of low-grade findings in the PZ+, PZ-, and control group was 80.0%, 58.3%, and 42.9% for mucosal damage, 85.0%, 41.7%, and 42.9% for a mild degree of inflammation, and 50.0%, 33.3%, and 4.8% for a shallow depth of inflammation, respectively. The PZ+ group tended to have milder mucosal damage than the other groups, according to all criteria used. In addition, significant differences were observed between the PZ+ and control groups regarding the endoscopic findings, degree of inflammation, and depth of inflammation.
  
  
  CONCLUSIONS
  This model was confirmed to be a useful experimental rat model for radiation proctitis. The results of the present study have demonstrated the efficacy of polaprezinc against acute radiation-induced rectal disorders using the rat model.
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Hyogo, Japan. h-doi@hyo-med.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Doi
authors.forename: Norihiko
authors.initials: N
authors.lastname: Kamikonya
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takada
authors.forename: Masayuki
authors.initials: M
authors.lastname: Fujiwara
authors.forename: Keita
authors.initials: K
authors.lastname: Tsuboi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inoue
authors.forename: Masao
authors.initials: M
authors.lastname: Tanooka
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakamura
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Shikata
authors.forename: Tohru
authors.initials: T
authors.lastname: Tsujimura
authors.forename: Shozo
authors.initials: S
authors.lastname: Hirota
mesh_terms: D000818:Animals; D000897:Anti-Ulcer Agents / Q000627:therapeutic use*; D002336:Carnosine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005260:Female; D009824:Ointments; D009942:Organometallic Compounds / Q000627:therapeutic use*; D011349:Proctitis / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology; D011833:Radiation Injuries, Experimental / Q000188:drug therapy* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012007:Rectum / Q000528:radiation effects*; D017967:Zinc Compounds / Q000627:therapeutic use
chemical_list: D000897:Anti-Ulcer Agents; D009824:Ointments; D009942:Organometallic Compounds; D017967:Zinc Compounds; C061957:polaprezinc; D002336:Carnosine